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Sunspot Group Detection and Classification by Dual Stream Convolutional Neural Network Method
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作者 Nyasha Mariam Mkwanda Weixin Tian Junlin Li 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第9期248-259,共12页
The automatic detection and analysis of sunspots play a crucial role in understanding solar dynamics and predicting space weather events.This paper proposes a novel method for sunspot group detection and classificatio... The automatic detection and analysis of sunspots play a crucial role in understanding solar dynamics and predicting space weather events.This paper proposes a novel method for sunspot group detection and classification called the dual stream Convolutional Neural Network with Attention Mechanism(DSCNN-AM).The network consists of two parallel streams each processing different input data allowing for joint processing of spatial and temporal information while classifying sunspots.It takes in the white light images as well as the corresponding magnetic images that reveal both the optical and magnetic features of sunspots.The extracted features are then fused and processed by fully connected layers to perform detection and classification.The attention mechanism is further integrated to address the“edge dimming”problem which improves the model’s ability to handle sunspots near the edge of the solar disk.The network is trained and tested on the SOLAR-STORM1 data set.The results demonstrate that the DSCNN-AM achieves superior performance compared to existing methods,with a total accuracy exceeding 90%. 展开更多
关键词 sun:magnetic fields sun:flares (sun:)sunspots DSCNN Attention mechanism Edge dimming
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Jovian Planet Influence on the Forcing of Sunspot Cycles
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作者 Fred J. Cadieu 《World Journal of Condensed Matter Physics》 CAS 2024年第1期1-9,共9页
The history of our solar system has been greatly influenced by the fact that there is a large gas giant planet, Jupiter that has a nearly circular orbit. This has allowed relics of the early solar system formation to ... The history of our solar system has been greatly influenced by the fact that there is a large gas giant planet, Jupiter that has a nearly circular orbit. This has allowed relics of the early solar system formation to still be observable today. Since Jupiter orbits the Sun with a period of approximately 12 years, it has always been thought that this could be connected to the nearly 11-year periodic peak in the number of sunspots observed. In this paper, the Sun and planets are considered to be moving about a center of mass point as the different planets orbit the Sun. This is the action of gravity that holds the solar system together. The center of mass for the Jupiter-Sun system actually lies outside the Sun. The four gas giant planets dominate such effects and the four gas giant Jovian planets can be projected together to determine an effective distance from the Sun’s center. Taken together these effects do seem to function as a sunspot forcing factor with a periodicity very close to 11 years. These predictions are made without consideration of any details of what is happening in the interior of the Sun. From these estimates, sunspot cycle 25 will be expected to peak in about September-October of 2025. Sunspot cycle 26 should peak in the year March of 2037. 展开更多
关键词 sun Cycles Solar System Formation JUPITER
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Variation in the Flaring Potential of Different Sunspot Groups During Different Phases of Solar Cycles 23 and 24
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作者 Abha Singh Anurag Chaudhari +1 位作者 Gyaneshwar Sharma A.K.Singh 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第2期144-153,共10页
In this present study,we have analyzed different types of X-ray solar flares(C,M,and X classes)coming out from different classes of sunspot groups(SSGs).The data which we have taken under this study cover the duration... In this present study,we have analyzed different types of X-ray solar flares(C,M,and X classes)coming out from different classes of sunspot groups(SSGs).The data which we have taken under this study cover the duration of 24 yr from 1996 to 2019.During this,we observed a total of 15015 flares(8417 in SC-23 and 6598 in SC-24)emitted from a total of 33780 active regions(21746 in SC-23 and 12034 in SC-24)with sunspot only.We defined the flaring potential or flare-production potential as the ratio of the total number of flares produced from a particular type of SSG to the total number of the same-class SSGs observed on the solar surface.Here we studied yearly changes in the flaring potential of different McIntosh class groups of sunspots in different phases of SC-23 and 24.In addition,we investigated yearly variations in the potential of producing flares by different SSGs(A,B,C,D,E,F,and H)during different phases(ascending,maximum,descending,and minimum)of SC-23 and 24.These are our findings:(1)D,E,and F SSGs have the potential of producing flares≥8 times greater than A,B,C and H SSGs;(2)The larger and more complex D,E,and F SSGs produced nearly 80%of flares in SC-23 and 24;(3)The A,B,C and H SSGs,which are smaller and simpler,produced only 20%of flares in SC-23 and 24;(4)The biggest and most complex SSGs of F-class have flaring potential 1.996 and 3.443 per SSG in SC-23 and 24,respectively.(5)The potential for producing flares in each SSG is higher in SC-24 than in SC-23,although SC-24 is a weaker cycle than SC-23.(6)The alterations in the number of flares(C+M+X)show different time profiles than the alterations in sunspot numbers during SC-23 and 24,with several peaks.(7)The SSGs of C,D,E,and H-class have the highest flaring potential in the descending phase of both SC-23 and 24.(8)F-class SSGs have the highest flaring potential in the descending phase of SC-23 but also in the maximum phase of SC-24. 展开更多
关键词 (sun:)sunspots-sun flares-sun activity-sun magnetic fields-sun filaments-prominences
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The Decay Process of an α-configuration Sunspot
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作者 Yang Peng Zhi-Ke Xue +8 位作者 Xiao-Li Yan Aimee ANorton Zhong-Quan Qu Jin-Cheng Wang Zhe Xu Li-Heng Yang Qiao-Ling Li Li-Ping Yang Xia Sun 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第2期73-81,共9页
The decay of sunspot plays a key role in magnetic flux transportation in solar active regions(ARs).To better understand the physical mechanism of the entire decay process of a sunspot,an α-configuration sunspot in AR... The decay of sunspot plays a key role in magnetic flux transportation in solar active regions(ARs).To better understand the physical mechanism of the entire decay process of a sunspot,an α-configuration sunspot in AR NOAA 12411 was studied.Based on the continuum intensity images and vector magnetic field data with stray light correction from Solar Dynamics Observatory/Helioseismic and Magnetic Imager,the area,vector magnetic field and magnetic flux in the umbra and penumbra are calculated with time,respectively.Our main results are as follows:(1) The decay curves of the sunspot area in its umbra,penumbra,and whole sunspot take the appearance of Gaussian profiles.The area decay rates of the umbra,penumbra and whole sunspot are-1.56 MSH day^(-1),-12.61 MSH day^(-1) and-14.04 MSH day^(-1),respectively;(2) With the decay of the sunspot,the total magnetic field strength and the vertical component of the penumbra increase,and the magnetic field of the penumbra becomes more vertical.Meanwhile,the total magnetic field strength and vertical magnetic field strength for the umbra decrease,and the inclination angle changes slightly with an average value of about 20°;(3) The magnetic flux decay curves of the sunspot in its umbra,penumbra,and whole sunspot exhibit quadratic patterns,their magnetic flux decay rates of the umbra,penumbra and whole sunspot are-9.84 × 10^(19)Mx day^(-1),-1.59 × 10^(20)Mx day^(-1) and -2.60 × 10^(20)Mx day^(-1),respectively.The observation suggests that the penumbra may be transformed into the umbra,resulting in the increase of the average vertical magnetic field strength and the reduction of the inclination angle in the penumbra during the decay of the sunspot. 展开更多
关键词 sun atmosphere-sun magnetic fields-(sun:)sunspots
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Django框架下的Sun求职平台构建与功能实现
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作者 梁孟晗 彭漠 +1 位作者 刘亚楠 于歌 《信息与电脑》 2024年第8期104-106,共3页
本文基于Django框架,设计与实现了Sun求职平台,旨在为求职者和招聘方提供一个高效、便捷的互联网招聘平台。通过采用Django的模型-视图-控制器(Model-View-Controller)架构,实现了用户注册、登录、简历上传、职位发布等核心功能。在前... 本文基于Django框架,设计与实现了Sun求职平台,旨在为求职者和招聘方提供一个高效、便捷的互联网招聘平台。通过采用Django的模型-视图-控制器(Model-View-Controller)架构,实现了用户注册、登录、简历上传、职位发布等核心功能。在前端方面,采用了Bootstrap框架进行页面布局,使界面简洁美观且具有响应性。在后端方面,利用Django的ORM系统实现了数据库的管理和交互,确保了系统的稳定性和安全性。通过整合第三方认证系统,提高了用户体验的同时,保障了信息的真实性。最终,Sun求职平台通过完善的功能和友好的界面,为求职者和企业搭建了一个高效的沟通桥梁,促进了人才与岗位的精准匹配。 展开更多
关键词 DJANGO 互联网招聘 sun求职平台 ORM系统
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The Influence of the Sun and Moon on the Observation of Very High Energy Gamma-ray Sources Using EAS Arrays
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作者 Tao Wen Songzhan Chen Benzhong Dai 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期245-252,共8页
With great advance of ground-based extensive air shower arrays,such as LHAASO and HAWC,many very high energy(VHE)gamma-ray sources have been discovered and are being monitored regardless of the day and the night.Hence... With great advance of ground-based extensive air shower arrays,such as LHAASO and HAWC,many very high energy(VHE)gamma-ray sources have been discovered and are being monitored regardless of the day and the night.Hence,the Sun and Moon would have some impacts on the observation of gamma-ray sources,which have not been taken into account in previous analysis.In this paper,the influence of the Sun and Moon on the observation of very high energy gamma-ray sources when they are near the line of sight of the Sun or Moon is estimated.The tracks of all the known VHE sources are scanned and several VHE sources are found to be very close to the line of sight of the Sun or Moon during some period.The absorption of very high energy gamma rays by sunlight is estimated with detailed method and some useful conclusions are achieved.The main influence is the block of the Sun and Moon on gamma rays and the shadow on the cosmic ray background.The influence is investigated considering the detector angular resolution and some strategies on data analysis are proposed to avoid the underestimation of the gamma-ray emission. 展开更多
关键词 astroparticle physics sun:general methods:observational sun:UV radiation
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Solving the Olbers’s Paradox, Explaining the “Red-Shift”, and Challenging the Relativities by “Sun Matters Theory” and “Sun Model of Universe”, an Evolution of the Einstein’s Static Universe Model
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作者 Wanpeng Sun 《Natural Science》 2024年第2期7-18,共12页
Olbers’s paradox, known as the dark night paradox, is an argument in astrophysics that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. Big-Bang theory was used ... Olbers’s paradox, known as the dark night paradox, is an argument in astrophysics that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. Big-Bang theory was used to partially explain this paradox, while introducing new problems. Hereby, we propose a better theory, named Sun Matters Theory, to explain this paradox. Moreover, this unique theory supports and extended the Einstein’s static universe model proposed by Albert Einstein in 1917. Further, we proposed our new universe model, “Sun Model of Universe”. Based on the new model and novel theory, we generated innovative field equation by upgrading Einstein’s Field Equation through adding back the cosmological constant, introducing a new variable and modifying the gravitationally-related concepts. According to the Sun Model of Universe, the dark matter and dark energy comprise the so-called “Sun Matters”. The observed phenomenon like the red shift is explained as due to the interaction of ordinary light with Sun Matters leading to its energy and frequency decrease. In Sun Model, our big universe consists of many universes with ordinary matter at the core mixed and surrounded with the Sun Matters. In those universes, the laws of physics may be completely or partially different from that of our ordinary universe with parallel civilizations. The darkness of night can be easily explained as resulting from the interaction of light with the Sun Matters leading to the sharp decrease in the light intensity. Sun Matters also scatter the light from a star, which makes it shining as observed by Hubble. Further, there is a kind of Sun Matters named “Sun Waters”, surrounding every starts. When lights pass by the sun, the Sun Waters deflect the lights to bend the light path. According to the Sun Model, it is the light bent not the space bent that was proposed in the theory of relativities. 展开更多
关键词 Olbers’s Paradox sun Matters Theory sun Model of Universe Einstein’s Universe Dark Mass
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New Insight to the Surface Temperature of the Sun
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作者 Ryszard Petela 《Energy and Power Engineering》 2024年第8期285-292,共8页
Information is given on thermal radiation from the Sun, considered in practical engineering calculations of heat exchange. It was found that although the surface temperature of the Sun is assumed to be about 5800 K, t... Information is given on thermal radiation from the Sun, considered in practical engineering calculations of heat exchange. It was found that although the surface temperature of the Sun is assumed to be about 5800 K, the solar spectrum data measured by Kondratyev lead to a value of at least 7134 K. Such a higher value can be obtained by interpreting the Planck formula for the black radiation spectrum for the Kondratyev data. In addition, using the Stefan-Boltzmann law, the energetic emissivity of the Sun’s surface was determined to be 0.431. Furthermore, based on Petela’s formulae for exergy of thermal radiation, the exergetic emissivity of the Sun’s surface was also calculated at the level of 0.426. 展开更多
关键词 Thermal Radiation Radiation Temperature Surface Temperature Surface Emissivity sun Radiation Spectrum Plank Law Exergy of Radiation Photosphere
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SunGas Renewables公司与C2X公司合作扩大北美绿色甲醇产能
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作者 程钰丹(译) 《石油炼制与化工》 CAS CSCD 北大核心 2024年第8期17-17,共1页
SunGas Renewables公司和C2X公司宣布建立战略合作伙伴关系,共同在北美开发和运营多个绿色甲醇生产设施,以增加可持续燃料的供应,并推进全球难减排行业的脱碳。SunGas Renewables公司是GTI Energy公司的分拆公司,是为可再生燃料生产提... SunGas Renewables公司和C2X公司宣布建立战略合作伙伴关系,共同在北美开发和运营多个绿色甲醇生产设施,以增加可持续燃料的供应,并推进全球难减排行业的脱碳。SunGas Renewables公司是GTI Energy公司的分拆公司,是为可再生燃料生产提供成熟工艺技术和设备的领导者。 展开更多
关键词 甲醇生产 可再生燃料 战略合作伙伴关系 sun 绿色
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Simulation and Performance Analysis of Six Types of Sun Tracker Approaches:A Comparative Analysis for Solar Concentrating Technology Application at Burkina Faso
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作者 Stanislas Sanfo Serge Dimitri Bazyomo +1 位作者 Tizane Daho Abdoulaye Ouedraogo 《Journal of Energy and Power Engineering》 CAS 2024年第1期1-8,共8页
Modelization equations of six approaches for tracking the sun are recalled and used to evaluate the constraints and performances to which they lead to.The geographical study case is taken for the specific latitude of ... Modelization equations of six approaches for tracking the sun are recalled and used to evaluate the constraints and performances to which they lead to.The geographical study case is taken for the specific latitude of 12 North that is a good matching with the location of the country of Burkina Faso.Three decisive periods were locally established in order to consider the different travels of the sun on sky during one year.This work presents some technical data which facilitates the choice of sun tracking approaches with concern of a concentrator limits such as its angle of acceptance,its motion control card interpolation model,or its minimum irradiation level for energy conversion effectiveness. 展开更多
关键词 Solar radiation sun tracker Burkina Faso experimental data
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上皮性卵巢癌组织中LRRC15、SUN2表达变化及其与患者预后的关系
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作者 赵萌 黄丹青 祝愿 《山东医药》 CAS 2024年第22期27-31,共5页
目的探讨富含亮氨酸重复序列15(LRRC15)、SUN结构域蛋白2(SUN2)在上皮性卵巢癌(EOC)组织中的表达变化及其与患者预后的关系。方法选取102例EOC患者手术切除癌组织(观察组),以60例因卵巢良性囊肿行手术治疗的正常卵巢组织为对照组。采用... 目的探讨富含亮氨酸重复序列15(LRRC15)、SUN结构域蛋白2(SUN2)在上皮性卵巢癌(EOC)组织中的表达变化及其与患者预后的关系。方法选取102例EOC患者手术切除癌组织(观察组),以60例因卵巢良性囊肿行手术治疗的正常卵巢组织为对照组。采用免疫组化法检测癌及正常卵巢组织中LRRC15、SUN2表达。通过Spearman秩相关分析评估LRRC15与SUN2表达的相关性,采用Kaplan-Meier生存曲线和Cox回归分析LRRC15、SUN2表达与EOC患者预后的关系。结果观察组LRRC15阳性率高于对照组,SUN2阳性率低于对照组,差异有统计学意义(P均<0.05)。观察组中LRRC15与SUN2表达呈负相关(r=-0.634,P<0.05)。LRRC15在EOC患者FIGO分期Ⅲ期、淋巴结转移中的阳性率高于FIGO分期Ⅰ~Ⅱ期、无淋巴结转移癌组织,SUN2在EOC患者FIGO分期Ⅲ期、淋巴结转移中的阳性率低于FIGO分期Ⅰ~Ⅱ期、无淋巴结转移癌组织,差异有统计学意义(P均<0.05)。LRRC15阳性组EOC患者3年总生存率低于LRRC15阴性组,SUN2阴性组EOC患者3年总生存率低于SUN2阳性组,差异均有统计学意义(P均<0.05)。FIGO分期Ⅲ期、病理分级Ⅲ级、淋巴结转移、LRRC15阳性是影响EOC患者预后的危险因素,SUN2阳性是保护因素(P均<0.05)。结论EOC患者癌组织中LRRC15表达升高、SUN2表达降低,LRRC15、SUN2表达与EOC肿瘤进展有关,检测二者水平有助于评估EOC患者预后。 展开更多
关键词 卵巢癌 富含亮氨酸重复序列15 sun结构域蛋白2 预后
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SunGas拟扩大美国绿色甲醇产能
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《化学反应工程与工艺》 CAS 2024年第3期201-201,共1页
近日,美国GTI Energy子公司SunGas可再生能源公司宣布与马士基集团控股子公司C2X建立战略合作关系,拟在美国开发绿色甲醇项目,旨在扩大美国绿色甲醇产能,增加可持续燃料供应,推动燃料行业脱碳。
关键词 战略合作关系 可再生能源 燃料供应 马士基集团 控股子公司 sun 甲醇项目 绿色
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Dark Galaxies, Sun-Earth-Moon Interaction, Tunguska Event—Explained by WUM
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作者 Vladimir S. Netchitailo 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第2期836-853,共18页
Great experimental results and observations achieved by Astronomy in the last decades revealed new unexplainable phenomena. Astronomers have conclusive new evidence that a recently discovered “dark galaxy” is, in fa... Great experimental results and observations achieved by Astronomy in the last decades revealed new unexplainable phenomena. Astronomers have conclusive new evidence that a recently discovered “dark galaxy” is, in fact, an object the size of a galaxy, made entirely of dark matter. They found that the speed of the Earth’s rotation varies randomly each day. 115 years ago, the Tunguska Event was observed, and astronomers still do not have an explanation of It. Main results of the present article are: 1) Dark galaxies explained by the spinning of their Dark Matter Cores with the surface speed at equator less than the escape velocity. Their Rotational Fission is not happening. Extrasolar systems do not emerge;2) 21-cm Emission explained by the self-annihilation of Dark Matter particles XIONs (5.3 μeV);3) Sun-Earth-Moon Interaction explained by the influence of the Sun’s and the Moon’s magnetic field on the electrical currents of the charged Geomagma (the 660-km layer), and, as a result, the Earth’s daylength varies;4) Tunguska Event explained by a huge atmospheric explosion of the Superbolide, which was a stable Dark Matter Bubble before entering the Earth’s atmosphere. 展开更多
关键词 World-Universe Model Dark Stars Dark Galaxies 21-cm Emission Formation of Macrostructures sun-Earth-Moon Interaction Tunguska Event Dark Matter
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基于SunSPOT无线传感器网络的水轮机组机械振动监测系统的研究 被引量:1
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作者 谢兴旺 刘好 《江汉大学学报(自然科学版)》 2013年第6期56-59,共4页
利用SunSPOT无线传感器网络硬软件平台开发了一套水轮机组机械振动监测系统。该系统能够对水轮机组转动部件的振动信息进行实时的采集、传输和存储。水电厂的控制中心对这些数据进行分析、处理并且作出判断决策,以确保水轮机组安全运行... 利用SunSPOT无线传感器网络硬软件平台开发了一套水轮机组机械振动监测系统。该系统能够对水轮机组转动部件的振动信息进行实时的采集、传输和存储。水电厂的控制中心对这些数据进行分析、处理并且作出判断决策,以确保水轮机组安全运行和适时检修,降低事故的发生概率。讨论了SunSPOT无线传感器网络硬件结构,6LoWPAN无线通信协议,基于Java语言的NetBeans软件开发平台以及SPOT WORLD虚拟机。介绍了终端节点的数据采集和传输,基站的数据接收和储存所用到的接口和类的代码。 展开更多
关键词 sunspot 无线传感器网络 机械振动 水轮机
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Predicting the 25th solar cycle using deep learning methods based on sunspot area data 被引量:2
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作者 Qiang Li Miao Wan +2 位作者 Shu-Guang Zeng Sheng Zheng Lin-Hua Deng 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2021年第7期290-298,共9页
It is a significant task to predict the solar activity for space weather and solar physics. All kinds of approaches have been used to forecast solar activities, and they have been applied to many areas such as the sol... It is a significant task to predict the solar activity for space weather and solar physics. All kinds of approaches have been used to forecast solar activities, and they have been applied to many areas such as the solar dynamo of simulation and space mission planning. In this paper, we employ the long-shortterm memory(LSTM) and neural network autoregression(NNAR) deep learning methods to predict the upcoming 25 th solar cycle using the sunspot area(SSA) data during the period of May 1874 to December2020. Our results show that the 25 th solar cycle will be 55% stronger than Solar Cycle 24 with a maximum sunspot area of 3115±401 and the cycle reaching its peak in October 2022 by using the LSTM method. It also shows that deep learning algorithms perform better than the other commonly used methods and have high application value. 展开更多
关键词 sun:activity sun:solar cycle prediction sun:sunspot area Method:deep neural network
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The causality between the rapid rotation of a sunspot and an X3.4 flare 被引量:3
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作者 Xiao-Li Yan Zhong-Quan Qu +2 位作者 Cheng-Lin Xu Zhi-Ke Xue De-Fang Kong 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第5期596-602,共7页
Using multi-wavelength data of Hinode, the rapid rotation of a sunspot in active region NOAA 10930 is studied in detail. We found extraordinary counterclockwise rotation of the sunspot with positive polarity before an... Using multi-wavelength data of Hinode, the rapid rotation of a sunspot in active region NOAA 10930 is studied in detail. We found extraordinary counterclockwise rotation of the sunspot with positive polarity before an X3.4 flare. From a series of vector magnetograms, it is found that magnetic force lines are highly sheared along the neutral line accompanying the sunspot rotation. Furthermore, it is also found that sheared loops and an inverse S-shaped magnetic loop in the corona formed gradually after the sunspot rotation. The X3.4 flare can be reasonably regarded as a result of this movement. A detailed analysis provides evidence that sunspot rotation leads to magnetic field lines twisting in the photosphere. The twist is then transported into the corona and triggers flares. 展开更多
关键词 sun sunspots - sun flares - sun magnetic fields
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Wavelet Analysis of Several Important Periodic Properties in the Relative Sunspot Numbers 被引量:16
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作者 Gui-MingLe Jia-LongWang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2003年第5期391-394,共4页
We investigate the wavelet transform of yearly mean relative sunspot number series from 1700 to 2002. The curve of the global wavelet power spectrum peaks at 11-yr, 53-yr and 101-yr periods. The evolution of the ampli... We investigate the wavelet transform of yearly mean relative sunspot number series from 1700 to 2002. The curve of the global wavelet power spectrum peaks at 11-yr, 53-yr and 101-yr periods. The evolution of the amplitudes of the three periods is studied. The results show that around 1750 and 1800, the amplitude of the 53-yr period was much higher than that of the the 11-yr period, that the ca. 53-yr period was apparent only for the interval from 1725 to 1850, and was very low after 1850, that around 1750, 1800 and 1900, the amplitude of the 101-yr period was higher than that of the 11-yr period and that, from 1940 to 2000, the 11-yr period greatly dominates over the other two periods. 展开更多
关键词 sun: sunspots - sun: activity - methods: data analysis
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Propagating slow sausage waves in a sunspot observed by the New Vacuum Solar Telescope 被引量:1
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作者 Song Feng Zheng Deng +2 位作者 Ding Yuan Zhi Xu Xiao Yang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第8期157-162,共6页
A sunspot is an ideal waveguide for a variety of magnetohydrodynamic waves,which carry a significant amount of energy to the upper atmosphere and could be used as a tool to probe the magnetic and thermal structure of ... A sunspot is an ideal waveguide for a variety of magnetohydrodynamic waves,which carry a significant amount of energy to the upper atmosphere and could be used as a tool to probe the magnetic and thermal structure of a sunspot.In this study,we used the New Vacuum Solar Telescope and took highresolution image sequences simultaneously in both Ti O(7058±10?A)and Hα(6562±2.5?A)bandpasses.We extracted the area and total emission intensity variations of sunspot umbra and analyzed the signals with synchrosqueezing transform.We found that the area and emission intensity varied with both three and five minute periodicity.Moreover,the area and intensity oscillated in phase with each other,this fact hold in both Ti O and Hαdata.We interpret this oscillatory signal as a propagating slow sausage wave.The propagation speed is estimated at about 8 km s^-1.We infer that this sunspot's umbra could have temperature as low as 2800–3500 K. 展开更多
关键词 sun:sunspot sun:oscillations magnetohydrodynamics(MHD) methods:data analysis
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Long-Term Sunspot Number Prediction based on EMD Analysis and AR Model 被引量:4
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作者 Tong Xu Jian Wu +1 位作者 Zhen-Sen Wu Qiang Li 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2008年第3期337-342,共6页
The Empirical Mode Decomposition (EMD) and Auto-Regressive model (AR) are applied to a long-term prediction of sunspot numbers. With the sample data of sunspot numbers from 1848 to 1992, the method is evaluated by... The Empirical Mode Decomposition (EMD) and Auto-Regressive model (AR) are applied to a long-term prediction of sunspot numbers. With the sample data of sunspot numbers from 1848 to 1992, the method is evaluated by examining the measured data of the solar cycle 23 with the prediction: different time scale components are obtained by the EMD method and multi-step predicted values are combined to reconstruct the sunspot number time series. The result is remarkably good in comparison to the predictions made by the solar dynamo and precursor approaches for cycle 23. Sunspot numbers of the coming solar cycle 24 are obtained with the data from 1848 to 2007, the maximum amplitude of the next solar cycle is predicted to be about 112 in 2011-2012. 展开更多
关键词 sun sunspots- sun ACTIVITY
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Low Dimensional Chaos from the Group Sunspot Numbers 被引量:2
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作者 Qi-Xiu Li Ke-Jun Li 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第3期435-440,共6页
We examine the nonlinear dynamical properties of the monthly smoothed group sunspot number Rg and find that the solar activity underlying the time series of Rg is globally governed by a low-dimensional chaotic attract... We examine the nonlinear dynamical properties of the monthly smoothed group sunspot number Rg and find that the solar activity underlying the time series of Rg is globally governed by a low-dimensional chaotic attractor. This finding is consistent with the nonlinear study results of the monthly Wolf sunspot numbers. We estimate the maximal Lyaponuv exponent (MLE) for the Rg series to be positive and to equal approximately 0.0187 ± 0.0023 (month^- 1). Thus, the Lyaponuv time or predictability time of the chaotic motion is obtained to be about 4.46 ± 0.5 years, which is slightly different with the predictability time obtained from Rz. However, they both indicate that solar activity forecast should be done only for a short to medium term due to the intrinsic complexity of the time behavior concerned. 展开更多
关键词 sun activity - sun sunspot - chaos - sun Wolf sunspot numbers
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